Research on Quantitative Risk Assessment and Prevention and Control Measure of Subsynchronous Oscillation

With the wide access of wind power and other renewable energy, subsynchronous oscillation accidents have occurred many times in power grid. Subsynchronous oscillation has a bad influence on the secure operation of power system. It has become one of the major factors restricting consumption of renewable energy. In order to suppress the occurrence of subsynchronous oscillation, the mathematical model of direct-drive permanent magnet synchronous generator (PMSG) is established, and then its impedance formula is derived. Based on impedance analysis, a quantitative risk assessment index for subsynchronous oscillation is proposed. On this basis, according to the sensitivity of control system's parameters to the quantitative risk assessment index, a preventive control measure to suppress the occurrence of subsynchronous oscillation is proposed. The feasibility of proposed control measure is verified.